Natural-Fibrous Lime-Based Mortar for the Rapid Retrofitting of Heritage Masonry Buildings

Abstract

The present work aims to define the mechanical behavior of a new composite material for the preservation and enhancement of the vast historical and architectural heritage particularly vulnerable to environmental and seismic actions. The new composite represents a novelty in the landscape of the fibrous mortars and consists of natural hydraulic lime (NHL)-based mortar, strengthened by Sisal short fibers randomly oriented in the mortar matrix. The developed mortar ensures the chemical-physical compatibility with the original features of the historical masonry structures (especially in stone and clay) aiming to pursue the effectiveness and durability of the intervention. The use of vegetal fibers (i.e., the Sisal one) is an exciting challenge for the construction industry considering that they require a lower level of industrialization for their processing, and therefore, their costs are considerably lower, as compared to the most common synthetic/metal fibers. Samples of Sisal-composite are tested in three-point bending, aiming to estimate both their bending stress and fracture energy. Tensile and compressive tests were also performed on the composite samples, while water retention and slump test were performed on the fresh mix. At last, the tensile tests on the Sisal strand were performed to evaluate the tensile stress of both strand and wire. An original mechanical interpretation is proposed to explain two interesting phenomena that arose from the analysis of experimental data. The comparison among the performances of unreinforced and reinforced mortar suggests that the use of short fibers is recommendable as coating in the retrofitting interventions alternatively to the long uni or bi-directional fiber strands adopted in the classic fibrous reinforcement (i.e., FRCM). The proposed composite also ensures mix-independent great workability, excellent ductility, and strength, and it can be considered a promising alternative to the classic fiber-reinforcing systems. As final remarks, the use of fiber F1 (length of 24 mm) with respect to fiber F2 (length of 13 mm) is more recommendable in the retrofitting interventions of historical buildings, ensuring higher strength and/or ductility for the composite.

Toward Nearly Zero-Waste Architecture: Innovation, Application, and Practice of Construction Methods Using Natural Materials

“…Trying new materials to innovate low-industrial construction techniques and lower costs is an exciting challenge for the construction industry. The earthquake-resistant effect of plant fibers on masonry buildings and the above two innovative characteristics have also been confirmed [38][39][40].…”

Study on the Durability of Hydraulic Lime Soil Mixed with Sodium Methyl Silicate

“…In this paper, the durability of hydraulic lime soil is improved by adding sodium methyl silicate, and the effect of sodium methyl silicate on its performance is studied, which provides a theoretical basis for the study of modified soil materials in the restoration and protection of earthen sites. Because the composite material has good mechanical properties and durability, it has wide application prospects in the restoration of soil sites and can be used to repair cracks, spalling, and other diseases of the walls of soil sites [21].…”

An Investigation of Mechanical Properties of Concrete by Applying Sand Coating on Recycled High-Density Polyethylene (HDPE) and Electronic-Wastes (E-Wastes) Used as a Partial Replacement of Natural Coarse Aggregates

“…They concluded that sustainable materials can be used for masonry strengthening. Vailati, M.; Mercuri, M.; Angiolilli, M.; Gregori, [38] discussed the use of Sisal short fibers in lime-based mortar. Mortar samples were tested in three point bending assembly.…”